--- a/NEWS Tue Mar 04 15:19:08 2025 +0100
+++ b/NEWS Tue Mar 04 16:07:55 2025 +0100
@@ -18,6 +18,7 @@
- Renamed lemmas. Minor INCOMPATIBILITY.
filter_image_mset ~> filter_mset_image_mset
- Added lemmas.
+ filter_mset_eq_mempty_iff
filter_mset_mono_strong
filter_mset_sum_list
set_mset_sum_list[simp]
--- a/src/HOL/Library/Multiset.thy Tue Mar 04 15:19:08 2025 +0100
+++ b/src/HOL/Library/Multiset.thy Tue Mar 04 16:07:55 2025 +0100
@@ -1337,6 +1337,9 @@
qed
qed
+lemma filter_mset_eq_mempty_iff: "filter_mset P A = {#} \<longleftrightarrow> (\<forall>x. x \<in># A \<longrightarrow> \<not>P x)"
+ by (auto simp: multiset_eq_iff count_eq_zero_iff)
+
lemma filter_filter_mset: "filter_mset P (filter_mset Q M) = {#x \<in># M. Q x \<and> P x#}"
by (auto simp: multiset_eq_iff)